


Deeper Still

by fuzipenguin



Category: Transformers Generation One
Genre: Aftercare, Blow Jobs, Cervix Fucking, Come Inflation, Cowgirl Position, Cunnilingus, Demisexuality, First Time, Incest, M/M, Multi, Multiple Orgasms, Open Relationships, Oral Sex, Other, POV Alternating, Sticky Sexual Interfacing, Transformers Spark Bonds, Twincest, Voyeurism, gestational tank fucking, kind of
Language: English
Status: Completed
Published: 2019-03-30
Updated: 2019-03-30
Packaged: 2019-12-27 00:52:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 9,924
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18293546
Author URL: https://archiveofourown.org/users/fuzipenguin/pseuds/fuzipenguin
Summary: It's a random series of events that leads them to this, but neither Grimlock or Sideswipe have any complaints.





	Deeper Still

**Author's Note:**

  * For [scraplet](https://archiveofourown.org/gifts?recipient=scraplet).



> \- The first part of this may be familiar to some readers as it is essentially chapter 27 of Tumbleweeds. I always wanted to expand that Sideswipe/Grimlock ficlet, but never really had plans for how exactly until now :)  
> \- Sponsored by Scraplet.

            “What him Sideswipe doing?” Grimlock asked, utterly perplexed when Sideswipe slid into the Dinobots’ rec area and clambered over several pieces of furniture before sliding to a stop behind him. He lifted Grimlock’s heavy tail and curled himself up under the base, making Grimlock produce an embarrassing squeak-growl at the intrusive action. He silently snarled at Slag when he perked up at the odd sound. 

              “Hiding. You don’t mind, do you?” Sideswipe whispered. The words were accompanied by a warm rush of ex-vented air directly over Grimlock’s hidden interface panel, and he somehow couldn’t find the impetus to remove the impertinent frontliner. 

             “What him Sideswipe hiding from?” Grimlock asked instead, very carefully not moving. Sideswipe’s frame was incredibly warm where it brushed against the inside of Grimlock’s legs. 

             “Shhhh!”

              Moments later, Grimlock heard the stamp of feet coming down the hallway. A shadow filled the rec room doorway and then Prowl leaned in, sharp blue optics sweeping the room. 

              “What him Prowl want?” Grimlock rumbled, not moving from his spot in front of the couch. With the piece of furniture blocking the way, Sideswipe was completely hidden from Prowl’s line of sight. And Grimlock’s sheer presence seemed to be keeping the 2IC from entering the room. 

              “Hello, Grimlock. Hello, Slag,” Prowl acknowledged politely. “Have you seen Sideswipe?” 

              “What him Prowl want with him Sideswipe?” Grimlock questioned, ignoring the frantic pokes to his ankle. Slag followed his lead in pretending Sideswipe wasn’t present and kept silent. 

               Prowl smiled, a humorous expression which showcased a great deal of denta. Grimlock approved. But he approved more of the warm, squirming mech crouched beneath his tail. 

               “I wish to speak with him regarding a prank. Jazz has had… an unfortunate incident involving industrial strength adhesive,” Prowl explained. 

               “Oh? Him Jazz stuck to wall?” 

               “No. More like he’s stuck to himself. His legs have been glued together,” Prowl elaborated. 

               Grimlock barked out a laugh. “Him Prowl more bothered than him Jazz, eh?” Grimlock commented, leering toothily at the tactician who was not so secretly involved with the head of SpecOps. A very quiet snicker arose from beneath Grimlock’s tail. Fortunately, Prowl was too far away, and too flustered, to hear. 

               Prowl’s optics widened and he took a step back. “I… no… that … it was dangerous! He could have been seriously hurt!” Prowl exclaimed, gaining momentum. “Anyway, if you see Sideswipe, please tell him to come see me.” 

               Grimlock nodded and Prowl left, continuing on down the hallway. When the sound of his footsteps had completely faded away, Grimlock bent and grasped Sideswipe by the shoulder, yanking him forward. Surprised, Sideswipe ended up sprawled on his back, looking up at Grimlock. 

               “Him Sideswipe - go see him Prowl,” Grimlock instructed, his head gesturing over his shoulder.

               Sideswipe’s startled expression morphed into a lopsided grin. “Yeah, boss, will do. Thanks for the assist.” He started to roll to his side, but Grimlock shifted and firmly planted a pede on that red abdominal armor. 

               “Hey-”

               “What him Sideswipe going to do for him Grimlock?”

               He snorted a hot ex-vent into Sideswipe’s surprised face, bending at the knees so he could suggestively trail fingers down Sideswipe’s neck. 

               Sideswipe swallowed audibly, fingers spasming on their grip around Grimlock’s ankle. “Um… well… whatcha want, buddy?”

               Grimlock smiled, liking the feel of the smaller mech continually pushing up against his pede. Mmm. This was a feisty one; he never backed down from a fight which Grimlock appreciated. And Grimlock had always liked the color red… 

               “I want you between my legs again.”

 

\--

 

                Sideswipe gaped at Grimlock for several seconds until his processor started back up again. Then he slipped his fingers beneath the plating covering Grimlock’s ankle. He quickly found and sharply pinched a motor line causing Grimlock to jerk backwards at the sting. Suddenly free, Sideswipe rolled to his feet and backed away until they were several arm lengths apart.

                “What happened to your voice?” Sideswipe asked, examining the Dinobot in front of him with wary curiosity.

                “My voice hasn’t changed,” Grimlock countered, his field teeking of smugness.

                Rolling his optics, Sideswipe gestured at him. “Ok, fine. You’re voice hasn’t changed. But you no longer sound like a kindergartner.” Had all the Dinobots been hiding this development? Did Ratchet and Wheeljack know?

                Did Optimus?!

                “I learned,” Grimlock said simply. His arms spread out as if to convey his harmlessness, but considered how short and tiny they were, it looked more like a seizure of the limbs. Sideswipe had to bite the inside of his cheek to not giggle. Somehow he got the feeling that wouldn’t go over well. Because Grimlock was definitely _not_ harmless.

                “… uh huh. Fine then. You learned. And have been hiding it. Whatever,” Sideswipe said, coming to the conclusion that he didn’t much care. “What exactly were you talking about just now?”

                “About getting you between my legs again?” Grimlock grinned, all sharp denta. “I liked having you down there the first time.”

                “What? Why? I didn’t do anything!” Sideswipe scoffed. Then he thought about it. “Oh, Primus, I actually have no idea if you even have interfacing equipment or where it’s at. Did I rev you up and leave you hanging?”

                Grimlock rumbled out a laugh, taking a step closer. Sideswipe couldn’t quite tell if he found the other mech’s looming hot or intimidating. Both his valve and his battle programs were clamoring at him for attention.

                “Something like that. I _do_ have interfacing equipment… and you were directly beneath it in this form.”

                Sideswipe’s gaze unconsciously flicked down to Grimlock’s tail before he could control his traitorous optics. So all that squirming around down there had basically been the equivalent of Sideswipe going up to Sunstreaker and stroking over his array cover. He winced.

                “Sorry about that. Still, though… me? Really?” Sideswipe asked doubtfully. The two of them never interacted socially and rarely even on the battlefield. The Dinobots did their thing and he and Sunny did their thing. But apparently a little light groping and Grimlock was 100% interested.

                “Really,” Grimlock replied. He tilted his head to the side and considered Sideswipe. Then he suddenly initiated his transformation. When the last plate clicked into place he stood two feet taller than Sideswipe and several feet wider.

                Annnnd… yup, Sideswipe’s valve was winning out. He had _just_ a little bit of a size kink.

                Grimlock made it even worse when he took several steps forward and placed his big hands on Sideswipe’s shoulders. He squeezed, making Sideswipe’s armor creak slightly. Then he trailed his fingers down Sideswipe’s arms, igniting a fiery tingle in the digits’ wake.

                “You’re attractive. And you’re sturdy so I don’t think I’d break you,” Grimlock mused.  

                Sideswipe snorted. “Half the ‘con army has tried, big guy. I don’t break easy.”

                Then a thought occurred to him. “All right, so you got the equipment – have you used it before?”

                Grimlock gestured to the now empty den. Somehow Slag had managed to lumber off and Sideswipe had missed it. Of course, the sudden realization that Grimlock actually _wasn’t_ the mental equivalent of a sparkling and getting propositioned by him was a pretty good distraction. “We have. We’re good at it.”

                “That remains to be seen,” Sideswipe muttered. He bemusedly watched as Grimlock stepped even closer, moving his hands down to Sideswipe’s hips. His field was warm and lapped at Sideswipe’s frame with little enticing waves of blatant invitation.

                “You want to see?”

                Sideswipe thought about it for several seconds, tossing around pros and cons. Then he gave a quick nod, one which Grimlock responded to with an eager growl. Sideswipe rapidly threw up a hand between them, halting Grimlock’s progress.

                “Hold on. One stipulation,” Sideswipe announced.

                Grimlock backed off so quickly that Sideswipe rocked in place a little from the displaced air. Hmmm… surprising, but nice to see Grimlock would take ‘no’ for an answer if need be.

                “Yes?”

                “Sunny and I are a matched set. You two wouldn’t be fragging each other, but he’ll be there,” Sideswipe explained. Many of their partners hadn’t known what to do with Sunstreaker spectating. Sideswipe was a little interested to see what Grimlock thought.

                Grimlock however, seemed to take it in stride. “That’s fine. Where? When?”

                Sideswipe hummed thoughtfully. “Second shift’s over in a few. Meet us at our quarters in two hours? Or is that too soon?”

                That would give him plenty of time to update Sunstreaker and let him primp if he wanted to. Oh, who was he kidding? Sunstreaker would be diving into the washracks as soon as he heard the news, regardless of the fact that he wouldn’t even touch Grimlock.

                “No, that sounds fine. Do I need to bring anything? Fuel…? Lube…?” Grimlock’s visor dimmed on one side and then brightened in a slow wink.

                Sideswipe reached out and patted Grimlock on the arm. “Got ya covered, buddy. Just bring your handsome self.”

                Grimlock rumbled again at the compliment and nodded. “That, I will do. I’ll see you soon.”

                Sideswipe flashed a grin at him and then strode over to the doorway, scanning the hall on either side. Confirming it was clear from copbots on the warpath, Sideswipe scampered through the door, internally mapping the best way to get to his quarters without running into Prowl and being detained.

                After all, he had a date that he didn’t want to miss.

               

\--

 

                “Sunny… really? I’m not _that_ dirty, am I?” Sideswipe asked, although he didn’t put up a fight. He just stood there and let his brother do his thing.

                Sunstreaker scrubbed furiously at a spot on Sideswipe’s lower thigh, face set in an expression of concentration. “You’re _filthy_. And I won’t let a partner into our berth unless both of us are at least passable. You know this,” Sunstreaker chided.

                Sideswipe gazed down at the top of Sunstreaker’s gleaming shoulders and sighed. “I know. I just thought I was already ‘passable’.”

                “You should realize that your definition of ‘passable’ is my definition of ‘abysmal’,” Sunstreaker returned, moving on to the outside of Sideswipe’s knee.

                “Mmhm. So… Grimlock, huh? I never saw that coming,” Sideswipe said idly, grabbing a sponge and going to work on his arms to help move things along. Sunstreaker seemed to be gearing up for a full-fledged wash and maybe even a wax. Sideswipe would rather not be dripping as he answered the door for Grimlock.

                Well.

                Not dripping suds or wax, anyway. His valve had steadily been getting wetter as the minutes passed by.

                “It _is_ interesting that he propositioned you,” Sunstreaker commented. “But I know you. I bet it didn’t take you long to take you to say ‘yes’, did it?”

                Sideswipe grinned at the washrack wall. “It took about ten seconds. I did actually consider saying ‘no’, you know. He’s big, and tough, and has several brothers who could easily pound us into spare parts if they ganged up on us.”

                Sunstreaker pushed himself to his feet, rinsing out his sponge. And ok, yeah, there was a pretty filthy puddle forming at their feet, so maybe Sideswipe had been dirtier than he’d originally thought.

                “Then I guess you have to make sure you blow his mind, hmm?” Sunstreaker remarked, one side of his mouth upturned in a smirk. On impulse, Sideswipe leaned in and kissed that tempting corner of his twin’s lips.

                “Not gonna help me?” Sideswipe questioned, turning the kiss into a nuzzle. Surrounded by steam and the familiar smell of their cleanser, Sideswipe’s array systems pinged to a secondary level of readiness, his spikehead nudging up against its closed cover. The two of them had ‘faced in their washracks on more than one occasion, the slide of hands over slippery plating leading to many memorable frags.

                A little appetizer before the main event couldn’t hurt…

                “Ow!” Sideswipe jerked back at the pinch to sensitive wires in his hip. He pouted at his twin and made grabby fingers in the air at him. “Aww… come on… we’ve got time.”

                “We do not,” Sunstreaker said tartly. “And you know I won’t join in. He’s an intriguing prospect, but I still don’t know him.”

                There was a flash of self-recrimination in Sunstreaker’s field before it was whisked away. Ignoring Sunstreaker’s irritated growl, Sideswipe grabbed his twin and pulled him in close, kissing him on the jaw.

                Sunstreaker didn’t do one night stands. Sideswipe could get revved up by a flirtatious glance from someone across the room, but Sunny had to know the other person first before he developed even an iota of sexual attraction. And even then it certainly wasn’t guaranteed. Bluestreak was their best friend, but Sunstreaker wrinkled his nasal ridge at the thought of berthing him.

                “That’s ok,” Sideswipe whispered fiercely against Sunstreaker’s audial. He pulsed waves of love across their bond, echoing it with a hard pulse of his spark. Sunstreaker was sure to feel it as closely pressed together as they were. “You know that’s ok with me.”

                “Is it ok with him?” Sunstreaker asked after a moment, slowly relaxing into Sideswipe’s embrace.

                “He said it was. Seemed to mean it too,” Sideswipe reported, thinking back on the interaction. “He’s got four brothers, after all. And apparently they’ve been fragging each other this whole time, so who knows who likes what.”

                “Mm.” Sunstreaker made a non-committal noise and Sideswipe squeezed him tightly before taking a step back and searching Sunstreaker’s face.

                “Hey. I love you. You know that, right?” Sideswipe said softly, the words almost obscured by the water beating down on them. He could tell Sunstreaker heard though; the corners of his optics softened and his mouth relaxed out of its frown.

                “Yeah, I know,” Sunstreaker mumbled, ducking his head and averting his gaze.

                Primus. Sunny could be ridiculously adorable when it came to dealing with feelings. It made Sideswipe want to give him all the things… and _do_ all the things to him.

                “Want me to show you?” Sideswipe purred, trailing a hand down his brother’s chest. His fingers spread out and he pressed his palm against the plating covering Sunstreaker’s lower abdomen, thumb suggestively stroking lower. “… passable, remember.”

                Sunstreaker wrapped his hand around Sideswipe’s wrist and he looked back up at Sideswipe through half-shuttered optics. After a beat, his lips curved up into something that could only be described as a helplessly fond smile.

                Sideswipe internally crowed. He had that effect on people; not even Sunstreaker was immune.

                “Well, since we’re aiming for just passable… I suppose we have time for you to show me how much you love me,” Sunstreaker murmured, ever so slowly exerting a downwards pressure on Sideswipe’s hand. Just as Sideswipe’s fingers skirted the edge of Sunstreaker’s panel, it slid aside, the sound of its transformation obscured by the streaming water.

                “Happy to be of service,” Sideswipe said, licking his lips. He dropped to his knees and eagerly proceeded with his demonstration.

 

\--

 

                Sideswipe was still getting a rub-down with a drying cloth when the doorchime rang. Sunstreaker made an irritated noise as Sideswipe ducked out from under Sunstreaker’s hands and practically ran across the room.

                So he was excited. So sue him. The more he thought about it, the more he was ready to get this party going. Especially since while he’d lavished attention on Sunstreaker, there hadn’t been time for his turn.

                He flung the door open so violently that Grimlock jerked back a step, tensing in alarm. Sideswipe just grinned up at him, practically vibrating in place.

                “Sideswipe, don’t scare the poor mech,” Sunstreaker sighed, coming up behind him and grabbing hold of the door’s edge as it started to rebound. “Please ignore my brother, Grimlock. He’s a heathen.”

                “Hey! The goal of this whole thing is for him to pay attention to me!” Sideswipe protested, mock glaring at Sunstreaker. When he glanced back at Grimlock, he saw the other mech slowly relaxing out of his instinctive defensive stance. “Sorry, big guy. You’ll find I can be a little overeager sometimes.”

                Grimlock looked him over and slowly nodded. “That’s not necessarily a bad thing. And you look good,” he commented.

                “Told you you were filthy,” Sunstreaker hissed before moving away.

                Rolling his optics, Sideswipe gestured at Grimlock. “Come on in, Grim. Want something to drink?”           

                He turned and took for granted that Grimlock would follow and shut the door behind him. Sideswipe skipped over to the decanter of high grade and cups he had sitting out, picking up an empty one and waggling it in the air.

                “That’s certainly a… different color…” Grimlock said, slowing to a halt several arms lengths away and staring at the decanter holding a gray-green liquid.

                “Oh, it’s the copper and manganese additives,” Sideswipe explained, pouring a small sample. He handed it over, grinning a little at Grimlock’s wary acceptance of the cube. “Gives it a nice kick. It’s good, I promise! Made it myself.”

                “Yes, but is it safe?” Grimlock asked, his blast mask sliding aside as he sniffed the cup’s contents.

                Sideswipe made a grinding noise in the back of his throat, and Grimlock looked up, startled. “What is it?”

                “You’re drooling,” Sunstreaker murmured in an aside to Sideswipe, passing between them as he headed to their couch.

                “You, ah… you have a nice… mouth,” Sideswipe said faintly, still staring. Grimlock’s lips were full and plush and Sideswipe had a sudden image of them wrapped around his spike.

                Those beautiful lips curled up at the corners in a smug smile as Grimlock took a sip. “Thanks… you have a nice… well… everything, really. Oh… this _is_ good.”

                As Sideswipe’s entire body flushed with a mix of embarrassment and pride, Sunstreaker laughed at him long their bond. He completely ignored the glare Sideswipe threw his way.

                “Thank you,” he said through gritted denta, looking back at Grimlock. “You’re welcome to more.”

                Grimlock tossed the rest of his cup back after giving it an appreciative glance. “Maybe later. There are other things I would like to taste, if you’re open to it.”

                He placed the empty cup down on the top of the desk and reached out to encircle Sideswipe’s wrist. Then he raised Sideswipe’s arm up and pressed a gentle kiss to his knuckles, Grimlock’s field enveloping him in warm admiration.

                The knuckle kissing absolutely did not made Sideswipe’s spark flutter. It did _not_.

                Sunstreaker laughed harder.

                _Shut_ up _, Sunny!_

                “Y-yeah?” Sideswipe cleared his intake. “So, um… how would you like to get started?”

                Grimlock glanced over Sideswipe’s shoulder at the freshly made berthcovers. “First… I wanted to ask… is there anything that you don’t want to do?”

                “Sparks,” Sideswipe answered immediately, which was the standard reply. “Other than that, you’re welcome to any part of me.”

                _All_ parts of him, Sideswipe hoped, staring at the breadth of Grimlock’s shoulders as he felt a finger absently caress the underside of his wrist. He shivered and the locks on his interface panel clicked open. He only kept the cover in place through sheer force of will.

                “And Sunstreaker…? You’ll… watch?” Grimlock ventured, showing the first real sign of hesitation since he walked into the room.

                Sunstreaker glanced up from his datapad and nodded. “I might piggyback on what Sideswipe is feeling over our bond, but I don’t want to be touched… at least not tonight.”

                Sideswipe’s gaze sharpened as it landed on his brother. Well, _that_ was interesting. Something in Sideswipe’s interaction with Grimlock must have resonated with Sunstreaker. Grimlock likely wouldn’t understand, but to Sideswipe, it was a clear indication that if things went well tonight, Sunstreaker would be open to them at least seeing Grimlock again.

                “Understood,” Grimlock said as Sideswipe reached out and took hold of his other hand. Sideswipe tugged, leading Grimlock over to the berth as he continued to gaze at Sunstreaker. “Please let me know if there’s anything you’d like to see me do to your brother.”

                Sunstreaker raised an orbital ridge while Sideswipe essentially ping-ponged around in their bond, buoyed by a billowing cloud of lust. He was always aware of Sunstreaker in his periphery, but he’d never actually _performed_ for him…

                “I’d honestly be happy for you to overload my brother as soon as possible so he could stop broadcasting in the back of my head,” Sunstreaker said dryly, giving Sideswipe a sharp mental poke.

                Sideswipe didn’t care. Not when Grimlock turned his attention on him, visor practically burning. “I can do that.”

                Sideswipe let go of Grimlock and scrambled backwards onto the berth. His cover finally snapped aside and he spread his knees in clear invitation.

                “That come off? Or do you need it to see? You don’t have it while you’re a T-Rex, so…” Sideswipe asked, pointing at the visor. His cooling fans kicked on with a quick whirl as he thought about rubbing himself off on it, his lubricant smearing over the visor’s surface. Of course, he’d be just as happy to do it on Grimlock’s bare face as well.

                “It does,” Grimlock said. He shifted and then kneeled on the floor between Sideswipe’s spread legs, removing the visor with one hand as the other clasped Sideswipe’s knee. “I do see better with it, but I don’t need perfect vision for this.”

                “For wha…ahhhh!”

                Sideswipe threw his head back as Grimlock bent forward and licked up the center of his valve. Blankly staring at the ceiling, Sideswipe didn’t fight Grimlock spreading his thighs wider to give himself more room. He’d honestly let Grimlock do anything he wanted as long as his hot, wet glossa kept lapping over Sideswipe’s main anterior node.

                Grimlock had apparently taken Sunstreaker’s request to spark and was wasting no time. Not that Sideswipe minded in the slightest. It didn’t take long for Sideswipe to realize that Grimlock hadn’t been lying earlier. He sucked and licked at Sideswipe’s valve with experienced lips and glossa, making Sideswipe’s elbows give out on him.

                He fell back onto the bed with a loud moan and Grimlock took the opportunity to lift Sideswipe’s heels up onto the edge of the bed. Sideswipe’s fingers scrambled at the back of Grimlock’s helm, hips rocking into each swipe of that wonderfully broad glossa.               

                “Ohhh… _frag_ … frag, that’s good…” Sideswipe muttered. His valve pulsed, trying to clench down on nothing and Grimlock obligingly slid a thick finger inside him. Sideswipe’s freely flowing lubricants made the penetration easy and his optics shut to savor the sensation.  

                “M-more… keep… oh, yesssss…” Sideswipe hissed as Grimlock added another finger. Sideswipe swiveled his hips in wild, needy grinds until Grimlock slipped his free hand beneath Sideswipe’s thigh. He curled his hand around and planted it on Sideswipe’s lower belly. As Sideswipe was pressed firmly into the bed’s surface, Sideswipe’s moans deepened in delight.

                It wasn’t often their partners could hold them still, but Sideswipe could tell that Grimlock would be able to easily manage it. Instead of frightening him, it just sent an illicit thrill through Sideswipe, rocketing his lust even higher.

                “I’m gonna… I’m gonna overload!” Sideswipe gasped, pelvis instinctively tilting to better expose his anterior node. Grimlock obliged him by fastening his lips around it and gently sucking while slipping a third finger inside him, stretching his walls. He shuddered as the rapidly building knot of pleasure deep in his belly contracted down tight, bringing him to the edge.

                So fast… it was going to end far too quickly, but it was so good that Sideswipe didn’t care.

                Then Grimlock hummed, the vibration of it reaching right up into Sideswipe, abruptly exploding that pulsing ball of need into a million pieces. Sideswipe’s back arched and he pulled Grimlock’s head even closer against him as he shouted and shuddered through his overload.

                He eventually slumped back down and Grimlock gentled him out of the high, moving away from Sideswipe’s sensitive node and lapping up the spill from his valve. Just when Sideswipe’s wits had started to gather themselves back together, Grimlock shifted and swallowed Sideswipe’s spike to the root.

                He couldn’t stop the embarrassing squeal that came out of him as he choked on his own glossa. The sudden ramp-up of pleasure made his lines burn and a second overload followed quickly on the tail of the first. When Grimlock finished sucking all of Sideswipe’s higher processing power out through his spike, he slowly removed his fingers and started licking them. All Sideswipe could do was pant and watch, spike twitching in a valiant attempt to repressurize at the sight.

                “That better?” Grimlock asked, glancing over his shoulder at Sunstreaker.

                “Much better actually, thank you,” Sunstreaker replied, sounding far too smug. To be honest, Sideswipe had benefited just as much from Sunstreaker’s flippant request, so he couldn’t find it in him to be offended. Not when Sideswipe’s head was just so much white noise.

                “… yeah…” Sideswipe croaked weakly. “… thanks.”         

                “My pleasure,” Grimlock purred, sounding like it really had been. He turned his attention back down to Sideswipe, slick-shiny lips curving up into a smile. “Now that I’ve warmed you up… would you be ok with me spiking you?”

                Sideswipe’s feet slipped off the edge of the bed and landed on the floor with a thud. “ _Fuck,_ yes. Just… put me where ever you want. You kinda broke me a little.”

                Grimlock reached for him, but then hesitated, staring down at Sideswipe’s valve. He frowned.

                “Hey… what’s wrong?” Sideswipe asked, voice finally gaining a little strength. With one big heave, he pushed himself upright and laid his hands on Grimlock’s shoulders. Even with him kneeling, Sideswipe was only a few inches taller. “I was kidding; you didn’t actually break me. What is it?”

                “You are… well, you’re not small. But you’re smaller than my brothers, even Swoop.” Grimlock remarked. “And I’m… I am also not small.”

                Sideswipe looked down to try and get a glimpse of Grimlock’s spike, but his interface panel was still in place. “I’m actually looking forward to it, babe. Don’t worry; I can handle it.”

                “I… I think it might be better if you were on top?” Grimlock offered, tilting his head to the side as he looked up at Sideswipe. “It would give you a little more control.”

                Sideswipe shrugged. He was pretty happy in any position, really. “Yeah, sure. Here, let’s get you comfy.”

                He rolled over to his hip and then to his knees and started gathering up their mess of pillows. Once he had a nice little nest up against the wall, he gestured Grimlock towards it. The Dinobot nodded his thanks and placed a knee on the berth. Then he hesitated again, staring down at it. It took a second for Sideswipe to figure out why.

                “They’re welded together. Wheeljack did it,” Sideswipe said in a burst of understanding. Their berth was actually two individual beds shoved together. Vigorous activity could easily push them apart if they weren’t adhered to one another.

                Sideswipe and Sunstreaker knew that as a fact; it’s why they had asked Wheeljack for a solution.

                “Ah,” Grimlock said and crawled onto the bed. He sat in the little nest, inclining back against the multitude of pillows. Once he got comfortable, he finally released his cover, and Sideswipe’s spark skipped a beat as he watched a truly beautiful spike begin emerging from its sheath.

                “Oh. Oh, yeah, you _are_ big,” Sideswipe breathed, fingers itching to touch. So he indulged himself, wrapping his hand around the yellow and gray shaft. It was so wide that his fingers didn’t even come close to touching his thumb. Even more impressive was the sheer length. As Sideswipe stroked it reverently, the spike grew to a size easily as long as Sideswipe’s arm from fingers to elbow.

                “Sideswipe… don’t hurt yourself,” Sunstreaker warned as Sideswipe started shuffling forward, optics intent on the beautiful specimen in front of him. Sideswipe glared over his shoulder as Grimlock chuckled a little in embarrassment.

                “I’m not an idiot; I know my limits!” Sideswipe returned. “… grab me the lube?”

                Sideswipe could have sworn he heard a mutter of ‘you don’t know the meaning of the word’, but Sunsteaker obediently got up from his seat on the couch and started to rummage in their toy box.

                “Imma have to thank Ratchet and Wheeljack after this,” Sideswipe said, beaming up at Grimlock. Oh, this was going to be _good_.

                “Ah… please don’t,” Grimlock said, squirming a little and ducking his head.

                Sideswipe’s grin widened and he couldn’t resist leaning forward to gently kiss the corner of Grimlock’s mouth. Grimlock froze for an instant before turning his head in order for their lips to meet. The kiss was surprisingly soft, and it was Sideswipe who deepened it, glossa licking into Grimlock’s mouth.

                Grimlock’s big hands slid around Sideswipe’s waist and he eagerly pressed close against the large mech’s chest as Grimlock kneaded his lower back. Sideswipe continued to lightly stroke Grimlock’s spike through their lingering kiss, thumbing up a drop of pre-transfluid when it leaked from the tip.

                They both jumped when something hit Grimlock’s leg, and Sideswipe looked down to see their half used bottle of artificial lubricant. He grabbed it up with a triumphant noise, sending Sunstreaker an absent minded ‘thanks!’ along their bond. As Sideswipe opened the bottle and tipped it over to drizzle lube down Grimlock’s twitching spike, Grimlock stroked Sideswipe’s outer thigh.

                “Truly… don’t hurt yourself,” Grimlock said earnestly. “We’re not in a rush.”

                Sideswipe rolled his optics as he spread the lube around evenly. “I really _do_ know my limits, Grim. I can take you widthwise, although I’ll need some time to adjust. Lengthwise though… that’s probably not gonna happen. Not completely.”

                “That’s fine,” Grimlock said. His voice was staticky at the edges, his optics bright as they watched Sideswipe’s fingers stroke up and down his shaft. He shivered every few seconds and Sideswipe vowed he’d make the other mech fall apart as nicely as Sideswipe had, either by his valve or some other part of him.

                Raising a challenging orbital ridge at Sunstreaker, Sideswipe held his twin’s gaze as he poured some lube over his fingers and pressed them into his valve.

                See? Sideswipe could be responsible. Lube everywhere and complete self-control on Sideswipe’s part.

                Well. At least partial self-control.

                Trembling in eagerness, Sideswipe shuffled closer on his knees. Grimlock obligingly closed his thighs together when indicated so Sideswipe could more easily straddle his lap.  

                “There. Good,” Sideswipe muttered to himself, placing a hand on Grimlock’s shoulder for support as he raised himself up. He positioned Grimlock’s spike at the entrance to his valve and slowly sank downwards onto it.

                He only took in the head, biting his lip against the initial sting. It was definitely big but he’d fragged big mechs before. Sideswipe had learned his lesson with Skyfire: a little at a time until his valve relaxed.

                Grimlock gripped Sideswipe’s waist at the initial penetration, hissing through clenched denta. “You’re so tight.”

                “I could argue that you’re just big,” Sideswipe countered, focusing on making his vents even.

                “Yes, you co-could… _oh_ …” Grimlock trailed off as Sideswipe let himself drop a little further. All of his nodes in his rim were sparking off happily and already the sting was fading into a pleasant burn.

                “I got this, Grim,” Sideswipe said reassuringly. Grimlock was staring at their groins with a frown of concern on his face. “Don’t worry.”

                “I’m… not worried,” Grimlock replied, gaze flicking up to meet Sideswipe’s. “I just don’t want to hurt you.”

                Sideswipe gently wriggled his hips from side to side, prompting Grimlock to swear and another inch to slip deeper into Sideswipe’s valve. “I’m pretty sure I’m… not hurt.”

                His cooling fans whirred quietly as Sideswipe’s internal temperature kicked up a notch. Not that it had really dropped all that much from his first overloads, but at least he didn’t feel like someone had thrown a car bomb on him anymore. Even though Sideswipe’s valve ached pleasantly, his third overload was still some ways off.

                “You doin’ ok?” Sideswipe asked. His thighs were starting to tremble with the effort of holding himself up, but that would fade once he got into a rhythm.

                “I’m fine. You’re… you feel amazing,” Grimlock murmured, his mouth opened as he continued to stare at where his spike was slowly slipping inside Sideswipe. “… hot.”

                “I am that,” Sideswipe remarked faintly, dutifully ignoring Sunstreaker’s snort. He shifted to better support himself as he gradually rose up until only the spike head was still inside him and then just as slowly, sank back down again. “Oh, _fuuuuuck_ …. that’s good…”

                Grimlock nodded rapidly, his fingers digging into Sideswipe’s waist. They threatened to dent the plating, especially when Sideswipe moved again, each pass becoming smoother. Every time he dropped down, he took in a little more of Grimlock’s spike, until Sideswipe was riding it with slow and steady motions.

                “Still ok, baby?” Sideswipe asked absently, his cooling fans picking up speed. He glanced at Grimlock to see him staring back, optics glassy. Grimlock’s glossa flicked out to lick his lower lip and he rumbled an assent, the vibrations making Sideswipe shiver.

                “Very much… you’re so beautiful.”

                Unexpectedly, the words hit Sideswipe like a blow and he shuddered, valve clenching down. Mecha called him ‘hot’ or ‘sexy’. Sunstreaker was the beautiful one, not him. He was usually the easy one, the stepping stone to his brother… something which never really worked out for anyone in the long run.

                “I… thanks…”

                Sideswipe looked away and concentrated on his lower half, absently leaning into Sunstreaker’s invisible caress for reassurance. Slightly distracted, Sideswipe abruptly bottomed out, his entire body freezing as the blunt spike head firmly tapped his ceiling node. He also might have made a small ‘eep’ of surprise, immediately catching Grimlock’s attention.

                “Are you alright?” Grimlock immediately demanded, one of his hands reaching up to cradle the side of Sideswipe’s face. Sideswipe’s gaze dropped and he almost squirmed from the show of concern.

                “Y-yeah, fine. But that’s pretty much all I can take,” Sideswipe said, looking apologetically at Grimlock. He reached down and fumbled between them, fingers trailing over the base of Grimlock’s spike. Barely a hand’s width left. Such a shame. That spike was so wonderfully thick and warm, and Sideswipe really wanted to grind in Grimlock’s lap, stir that thickness inside of him.

                “It’s no small amount,” Grimlock replied, sounding choked up.

                “Mm. Definitely not small,” Sideswipe murmured. His head slipped back and his optics closed as he bounced on Grimlock’s spike a little, enjoying the stimulation to his ceiling node. “You about ready?”

                “Ready for what?” Grimlock asked, and Sideswipe’s lips curved up in a secretive smile. Instead of answering, he leaned farther back, supporting himself by a hand apiece on Grimlock’s knees. Then he lifted his hips and started really moving with long passes of his valve up and down Grimlock’s spike.

                Grimlock groaned loudly, sounding wounded as Sideswipe quickly found his rhythm. The good kind of wounded though, the kind accompanied by murmured gratitude and whispered encouragements. The kind Sideswipe could happily ride all the way to his own overload, while ever so surely breaking his partner’s processor every time he swiveled his hips… just… so…

                “I bet… I bet you’ll have a big load… huh?” Sideswipe asked, optics still shut as he rippled his valve calipers. Grimlock moaned wordlessly, hands returning to Sideswipe’s waist to hang on as he moved. “… think you could lick it out of me later?”

                Sideswipe wanted to see Grimlock’s expression, so he shifted slightly to the side in preparation of pushing himself better upright. As he did, the flare of Grimlock’s spike tip rubbed over Sideswipe’s closed gestational chamber orifice. It shot a bolt of sensation straight up his spinal strut, a moan of his own slipping past his lips.

                The gestational tank entrance was at the top of his valve, recessed enough so that it was rarely stimulated. The last time Sunstreaker had fisted him, his fingers had accidentally managed to reach it, stimulating both his ceiling node and the iris at the same time. Sideswipe had thought it had been the press against his node which had pushed him into a screaming overload, but now Sideswipe felt he might need to rethink that assessment.

                He supposed it made sense; there had to be a ton of sensors lining the chamber that monitored a carrier’s newspark. So it served to reason that those sensors would be sensitive. And that manipulating them in a certain way could be pleasurable.

                Sideswipe had never really thought about his gestation tank in great detail before. But now he let his body move on autopilot as he searched his directory systems for the chamber’s operating programs. A quick perusal showed him several lines of code, all medic flagged.

                Of course, Sideswipe had lifted medic codes from a variety of different doctors over the years and it only took two tries for him to trigger the manual release of the passage into his chamber.

                Just in time for his next downward thrust to partially butt up against the widening hole. The burst of pleasure at the barely there touch caused his body to involuntarily shift so that the orifice lined up directly over Grimlock’s spike on the next drop. Sideswipe experienced a momentary resistance and then Grimlock’s spike popped passed it, directly into his tank.

                And then Sideswipe’s wish came true. His aft now rested completely on Grimlock’s upper thighs, the entire length of his spike spearing up into Sideswipe’s body.

                If the pleasure hadn’t immediately overtaken his processor, he might have been a little disturbed. But honestly, all thought had just let the building. The only thing that remained was the sensation of his entire haptic net being doused in icy hot bliss. 

 

                --

 

                 Grimlock decided that he had been missing out. Interfacing his brothers had always been good and comfortable, but interfacing Sideswipe was an entirely different story. His frame was burning hot, each motion graceful and powerful. He was obviously smaller than Grimlock, but although he initially used caution, it didn’t take him long to really get moving. And his hot, silken valve molded to every ridge of Grimlock’s spike as if they were made for one another.

                 Sideswipe had apologized to him for being unable to fully take Grimlock’s length, something Grimlock found ridiculous. Even his brothers were sometimes uncomfortable being on the receiving end of it, mechs who were taller and broader than Sideswipe. Yet Sideswipe’s body made room for the majority of it as if it were nothing.

                And then abruptly, Sideswipe’s body accepted Grimlock’s spike to the root. Grimlock might not have even noticed at first except the loud screech Sideswipe made was pretty attention getting. That and the sudden appearance of Sunstreaker at the side of the bed, hands outstretched towards his twin. He didn’t quite touch him, however; he just stared at Sideswipe’s frozen form, optics wide and worried.

                As the echoes of Sideswipe’s cry faded, Grimlock finally registered that Sideswipe was completely seated atop him.

                “Wh… Primus… what…?” Grimlock’s processor turned so slowly he thought it had regressed to its original, immature state. He couldn’t comprehend what had happened and only felt a creeping horror that he had somehow grievously injured Sideswipe.

                “Is he hurt? Should… should I call Mom?” Grimlock unthinkingly asked, instinctively opening a communication line to Ratchet. “Sideswipe? Sideswipe, did I hurt you!?”

                Sideswipe’s hand slipped down Grimlock’s shoulder and weakly waved through the air in a negative. But he was completely still otherwise, entire face set in what looked to be a pained grimace. Grimlock couldn’t get a good read on Sideswipe’s field either; it kept changing, too rapidly for Grimlock to keep up.

                “…no.”

                Grimlock automatically looked to Sunstreaker to confirmation. Sunstreaker ever so gradually dropped his arms, forehelm furrowing as he continued to stare at his twin. “Sides…” he said slowly, “… what did you do?”

                Sideswipe whined and then feebly gestured at his abdomen. “…opened… _fuck_ …”

                He experimentally rose up before either of them could stop him. Grimlock frantically grasped at Sideswipe’s hips to hold him still after his back bowed with what Grimlock thought was a pained cry.

                “Sides, don’t! Primus… oh Primus, I’m killing you…” Grimlock whispered, horrified.

                “Don’t be ridiculous,” Sunstreaker retorted. “He’s not injured – do you see any energon?”

                Grimlock automatically scanned his pelvis, but even though Sideswipe was tight around him, a significant bleed would still have started leaking out by now. There was a copious amount of both natural and false lubricants everywhere, but no energon.

                “No, but… I don’t understand. You’re sure he’s not hurt?”

                Sunstreaker closed his optics, tilting his head to the side. He abruptly swayed in place before grabbing hold of Sideswipe’s shoulder, optic shutters popping back open in shock.  

                “He’s good!” Sunstreaker gasped. “He… he somehow figured out how to open his gestational chamber which is how he’s managing to fit all of you. And it’s… well, it _definitely_ doesn’t feel bad.”

                “He… he likes it?” Grimlock ventured, still unnerved by Sideswipe’s near continuous high-pitched whine. Sideswipe batted at Grimlock’s hands and Grimlock automatically loosened his grip. He landed back atop Grimlock’s lap with a grunt, curling forward a little.

                “… love it,” Sideswipe moaned. A tremble started up in his frame, sweeping over him in waves. “… trust me… I…”

                His engine revved up to a high pitch and he finally opened his optics, staring at Grimlock with unaltered awe. “…so good… Grim… it’s so good… I might die…”

                Sideswipe moved in a small grind, the light in his optics blazing and their color fading to nearly white. His jaw dropped, and he panted heavily as he stared down at himself. “Primus… Primus, look at that,” Sideswipe said, voice hushed. “Look… all of you…”

                He leaned forward more, shuddering as it shifted Grimlock’s spike inside him. Sideswipe’s fingers anchored themselves in Grimlock’s shoulder seams as he raised his hips a few inches and slammed them back down. Almost involuntarily, his back arched, helm lifting. He looked to be gazing at Grimlock’s face, but Sideswipe’s optics were hazy, his attention completely focused inward.

                Tiny arcs of blue charge sprang to life across Sideswipe’s frame as he haltingly rode Grimlock’s spike. The motions were not as smooth as before; every time Sideswipe bottomed out, he paused, shaking and shivering for several seconds before seeming to gather the strength to move again.

                “… I could do it,” Grimlock offered, entranced more with Sideswipe’s expression than the hot clasp of his body. He slid his hands down, easily cupping the back of Sideswipe’s thighs and lifting him about six inches up his spike and holding him there in demonstration.

                It Sideswipe was truly uninjured… if he was really enjoying this… Grimlock would do anything he could to make it easier on him.

                Sideswipe’s gaze sharpened a little and he nodded after a moment, glossa flicking out to wet his lower lip. “Yeah. Yeah… that’s… just don’t… don’t stop, k? Want you… you to come in me… here…”

                Sideswipe shakily reached down and tapped his lower abdominal plating, the area over his gestational chamber. Grimlock imagined it, pulling him down onto his spike… pushing deep into Sideswipe’s body and overloading there… directly into his tank. They all had contraceptive codes in place, but something feral in Grimlock reared its possessive head with a surge of triumph.

                Growling a little, Grimlock helplessly thrust up into Sideswipe’s welcoming valve. He completely hilted himself with ease, and Sideswipe’s mouth opened on a spiraling keen as his optics rolled back into his head. Sideswipe looked utterly taken by the pleasure, giving in to it completely. Grimlock could do nothing but provide more so he pumped into Sideswipe’s valve again.

                And again. And again until about seven thrusts later, Sideswipe threw his head back and wailed as his frame rattled in overload. Sideswipe’s valve clamped down so hard it bordered on painful, so Grimlock paused, venting harshly as charge crackled along his armor everywhere they touched

                As his cry faded and his calipers slowly spasmed open, Sideswipe started to slump, slipping to the side. Grimlock flailed a bit in the sink of the pillows, trying to sit up and better support Sideswipe. He needn’t have worried; Sunstreaker beat him to it.

                Golden arms slipped around Sideswipe’s upper body, propping his back against Sunstreaker’s chest. Sunstreaker peered down at him, his optics also brighter as he presumably ‘piggybacked’ on his brother’s sensory input.

                “Don’t read anything into it,” Sunstreaker warned, his knees pressed tightly against the outside of Grimlock’s thighs. “I’m just here for him.”

                Words were pretty difficult at the moment so Grimlock just nodded. He resumed thrusting up into Sideswipe’s valve and discovered his partner however, had relearned how to speak.

                “Oh god… _Primus_ … please yes, that’s so good,” Sideswipe moaned in one rush of babble. “I can’t even… I just… it’s so _good_ …nnnnggghh…!”

                Sunstreaker’s left hand slipped down Sideswipe’s chest and pressed against his lower abdomen. Sideswipe’s arms immediately went limp as a result, dropping down to his sides. He made a sound like a dying rabbit as he leaned back further into Sunstreaker’s embrace.

                “I can feel it,” Sunstreaker murmured to Sideswipe, trying to peer down the length of his twin’s body. His hooded gaze flicked up to Grimlock’s face, just for an instant. “Just barely, but I feel it every time he goes deep.”

                Grimlock thought maybe there was an increase of pressure around his spike head as Sunstreaker pressed harder, but that was likely imagined. The twins’ plating was not as thick as his, but still warrior grade. It would take far more than a simple touch of someone’s hand to squeeze Sideswipe’s internals.        

                And yet… Grimlock burned at the sight of Sunstreaker’s fingers separated from his spike by mere inches. Direct touch had been forbidden and Grimlock would respect that, but he suddenly desperately wanted the sensation of Sunstreaker’s plating beneath his hands as he plundered the depths of his twin’s valve.

                The thought made him buck upwards harder and faster and Sideswipe sobbed wordlessly. He turned his head and blindly pressed his forehelm against his brother’s cheek, mouth opened wide and the most delicious sounds pouring forth.

                “…fuck, fuck, _fuck_ … oh, again… _yespleaseagain!”_ Sideswipe cried out, hips beginning to restlessly twitch into each of Grimlock’s thrusts. His field unfurled against Grimlock’s, hot and heavy and oh so needy.

                Grimlock couldn’t do anything but oblige him.

                It didn’t take long for Sideswipe to overload, a garbled, choked off shout ripping through him. He shivered and shook for well over a minute, his entire body spasming at random intervals until the high began fading and he slowly went limp again.

                Sideswipe’s head hung down as if he couldn’t support it and Grimlock spied a single thread of drool touch his chest as Sunstreaker adjusted his grip on him.

                “Is he still ok?” Grimlock asked. Sideswipe’s valve intermittently clenched around his spike, but he was loose enough for Grimlock to resume. He was pretty close to his own overload, but he would stop if either of them indicated Sideswipe was uncomfortable or needed to pause.

                “Mm. He’s fine,” Sunstreaker mumbled. He absently lipped at Sideswipe’s closest audial horn, causing Sideswipe’s upper body to sinuously arch. “… keep going.”

                Trusting Sunstreaker to know his twin best, Grimlock resumed pumping in and out of Sideswipe’s valve. There was a copious amount of lubricant pouring out of him, mostly natural by now. It pooled on Grimlock’s lap, seeping down through his armor gaps. He didn’t mind; it was just more evidence that Sideswipe was having a good time.

                A good time that Grimlock hoped would become even better. He pushed off his own climax, greedy to see Sideswipe come once more. The sight of Sideswipe so overwhelmed by pleasure was in itself just as good as the hot clench of his valve around Grimlock.

                “Touch his node,” Grimlock suggested in a sudden burst of inspiration as he spied Sunstreaker’s hand still resting on Sideswipe’s belly. Sideswipe made a quiet sound and his right arm feebly moved backwards, clanging against Sunstreaker’s side. Probably a wordless encouragement since Sunstreaker almost immediately complied, his fingers inching downwards.

                His first two fingers brushed over the bright red, throbbing nubbin and Sideswipe sighed deeply, letting his head rest against Sunstreaker’s shoulder. His optic shutters parted slightly and Grimlock saw Sideswipe’s glittering gaze struggle to focus on him.

                “You going to come again?” Sunstreaker asked softly, gently circling the node in small passes. “I’m honestly surprised how quiet you’ve been...gearing up for a big finish?”

                Grimlock blinked in surprise because in his opinion Sideswipe had already been _quite_ vocal. Sideswipe could get louder?

                “… nngh… polite…”

                “I don’t think he’ll mind,” Sunstreaker replied to Sideswipe’s nearly incoherent mumble. His gaze met Grimlock’s and his lips curved up at the corners in a smirk. “Come on, Sides… let go…for him… for _me_ …”

                Sunstreaker’s fingers firmly rubbed directly over the node, and Sideswipe’s back slowly bowed, his fingers forming claws and digging into his brother’s arms. After a loving nuzzle to Sideswipe’s cheek, Sunstreaker turned and captured his lips in a bruising kiss. Grimlock’s spike jerked at the scintillating sight and his thrusts turned erratic, less controlled.

                The next overload hit Sideswipe out of nowhere and he broke away from his brother’s mouth, screaming loud enough that the entire base probably heard him. The cry of abandon went up a pitch as Grimlock continued to thrust past the clench of those tight valve calipers. He couldn’t help it; he couldn’t hold his own overload back any longer and his body was moving of its own volition.

                Fortunately, Sideswipe didn’t seem to mind.

                “I… oh, Primus… Sideswipe!” Grimlock shouted when the climax finally crested over him. He pushed deep one last time and roughly pulled Sideswipe down onto his lap. The first pulse of transfluid felt so good it almost hurt and he curled forward, forehelm resting against Sideswipe’s chest.

                Sideswipe’s keen choked off as his body abruptly seized. His valve started rippling, beginning at the entrance and traveling deeper in waves. Likely meant to direct the flow of transfluid into his gestational chamber but of course, Grimlock was already directly depositing his spill there. Every drop that he had, until his reservoir tank ached in emptiness.  

                “Full… so full…” Sunstreaker moaned. Sideswipe’s entire frame jerked with a grinding hiccup of his engine, and Grimlock dimly realized that Sideswipe was overloading again. He couldn’t manage to open his optics to watch this time, but he felt it in every spasm of Sideswipe’s body, heard it in every stuttered moan, every rasp of Sideswipe’s fully opened vents.

                 Eventually, the full force of their overloads faded and all three of them slumped together. Grimlock felt blissed out, but not enough that didn’t feel a growing concern for his partner. Even after Grimlock’s spike stopped pulsing, Sideswipe continued to twitch, as if random bursts of charge still ran through his body.

                 Grimlock manage to creakily push himself upright and Sideswipe tilted forward, resting against his chest. Sunstreaker no longer held him up. In fact, Sunstreaker seemed almost as lifeless as his brother, face hidden from view against Sideswipe’s back. He still had a grip on his twin however, and moved along with him as Grimlock leaned back, cradling Sideswipe to his front.

                Sideswipe was a hot and heavy weight atop him, but Grimlock didn’t particularly care. He stroked the back of Sideswipe’s helm and tried to shift him so he could get a look at his face. It was a little disturbing how quiet he was after all the earlier shouting.

                “… Sideswipe?”

                “… ‘s fine,” Sunstreaker slurred, finally stirring. He sluggishly pushed himself upright, aft plopped squarely on Grimlock’s thighs.

                “Are you sure?” Grimlock asked, unnerved to see Sideswipe’s limbs continue to jerk randomly. He admittedly hadn’t had a lot of interfacing partners, but none of his brothers had ever looked so… _broken_ after a frag.

                “Is he normally like this?”

                Sunstreaker shakily raised a hand and wiped his face. He contemplated his brother for a long moment before finally shaking his head. “No, he’s…”

                Sideswipe let out a low moan and shivered when Sunstreaker lightly stroked fingers down his back. “It’s like every part of him is a single raw, live wire,” Sunstreaker mused. His gaze flicked back up to Grimlock and his expression softened. “… in a good way. You didn’t hurt him.”

                “What should we do now?” Grimlock asked, uncertain. He wanted to care for his obviously incapacitated partner, but hadn’t the slightest idea where to even start.

                Sunstreaker raised an orbital ridge and proceeded to slide off the berth. He swayed as he stood and Grimlock spied smears of fluids on his inner thighs despite his panel being closed. “We? I don’t know about you, but I’m going to find some cleaning supplies because this is going to be a mess shortly,” he said, gesturing towards Grimlock’s lap.  

                Grimlock supposed he was right. As his spike started to depressurize, he could feel a mix of transfluid and lubricants seeping out of Sideswipe’s valve. And as comfortable as Sideswipe seemed, Grimlock figured he would appreciate being cleaned up.

                Gathering his strength, Grimlock gripped Sideswipe by the waist and started lifting his lower body. Sideswipe loudly whined, the sound culminating in a garbled scream as Grimlock tucked his pelvis and completely withdrew from Sideswipe’s valve. Another convulsion wracked Sideswipe’s frame and more waves of blue charge swept down his body to crackle against Grimlock’s fingers.

                Grimlock gaped up at the ceiling in astonishment. A live wire, indeed.

                Murmuring nonsense reassurances, Grimlock tucked Sideswipe against his chest, his plating vibrating as shivers wracked Sideswipe’s body. Thinking the mess would be less if gravity weren’t a factor, he slowly rolled them and guided Sideswipe onto his back.  

                Sideswipe’s optics were half open, but he couldn’t seem to track Grimlock’s hand when he slowly waved it in front of his face. His right arm jerked and his hand flailed at his own pelvis, fingers brushing over his array. He breathed out a low moan, legs languidly shifting.

                “Sideswipe?” Grimlock asked softly, trailing a hand down Sideswipe’s chest to his abdomen. His lower belly bulged slightly and Grimlock cupped the small mound. He marveled at it, rubbing a thumb over a straining plating seam. “Can you talk?”

                “This might be one of the few times in his life that he can’t,” Sunstreaker said, slipping back onto the bed as Sideswipe made another whining noise. Sunstreaker dumped the supplies he had been carrying onto the berth cover, rummaging through them until he picked up a moderately sized black plug.

                “What are you doing?” Grimlock asked curiously as Sunstreaker poured a bit of artificial lube on the tip and rubbed the substance over the rest of the toy.

                “He hates feeling empty after being stretched so wide,” Sunstreaker explained as he placed the plug to the entrance of Sideswipe’s valve and slowly slipped it in. Sideswipe stiffened at the initial penetration and then melted back into a strutless heap, humming happily. A moment later, his engine kicked over into a raspy purr as Sunstreaker started cleaning him up.

                Sunstreaker ran a damp cloth over Sideswipe’s plating in long, firm strokes, moving confidentially as if he had done this multiple times before. After wiping away the majority of the mess, he then used a second towel to wick up any remaining moisture. Finally, Sunstreaker gently tapped the plating just above Sideswipe’s array and his cover snapped closed, trapping the plug and remaining fluids inside.

                So entranced with watching Sunstreaker lovingly care for his twin, Grimlock was surprised when another damp cloth was shoved in his face. He automatically took it, staring at Sunstreaker.

                “… thanks.”

                Sunstreaker shrugged and turned his attention to himself, quickly cleaning his own plating as Grimlock followed suit.

                “Did you…?” Grimlock ventured, curious.

                Sunstreaker’s hands paused for a split second before resuming their motions. He didn’t look up at Grimlock, and his voice was quiet. “I don’t necessarily overload while experiencing his. Sideswipe would if he were in my position, but…”

                Sunstreaker ruefully shook his head. “Sometimes I think Sideswipe could overload walking across the room if he was revved up enough. Anyway, this is all from the two of you. Sideswipe got lost in all of that and I didn’t want to go too deep with him in case something happened. So both yes, and no.”

                Grimlock gazed at the top of Sunstreaker’s bent helm and felt his body go warm in a different way than from lust. “You are a good brother.”

                Sunstreaker’s head shot up and he stared at Grimlock in astonishment. Grimlock cleared his throat and abruptly looked away, focusing in on Sideswipe’s slack mouth. “I mean… I…”

                “No, it’s… thank you. It’s not easy… he can be an idiot sometimes.”

                Grimlock snorted, peeking at the other mech with a tentative smile. “You only have one. Try four.”

                “No, thank you,” Sunstreaker replied feelingly. “Here… are you done?”

                He took the dirty rags and supplies and carried them across the room. When Sunstreaker returned, he stood there for a moment before gesturing imperiously at Grimlock. “Slide over. And take him with you.”

                A little bemused, Grimlock nevertheless obeyed, scooting across the bed until his back met the wall. Sunstreaker helped moved Sideswipe, rolling him over and tucking himself in behind his twin’s back. When they settled, Grimlock cautiously rested a hand on Sideswipe’s hip. His elbow was awkwardly bent against his side but he also didn’t want to impose on Sunstreaker’s ‘no touching’ mandate.

                Sunstreaker broke it himself. With a sigh, he grabbed Grimlock’s hand and pressed it against his lower back. It allowed Grimlock to better curl around Sideswipe and keep his arm in a much more comfortable position.

                “It doesn’t mean anything,” Sunstreaker murmured from where his face was pressed against Sideswipe’s nape. One violet blue optic stared up at Grimlock, the light of it beginning to dim. “Thank you… for taking care of him.”

                The words were begrudging, but Grimlock felt that warmth suffice him again. He decided that he _definitely_ would like a repeat of this if they would have him. And not just interfacing; he thought that he would enjoying interacting with both of them out of the berth as well.

                “You’re very welcome,” Grimlock replied quietly, holding Sunstreaker’s gaze. “And thank you for letting me stay.”

                Sunstreaker’s optic closed and he nuzzled the back of Sideswipe’s neck, prompting his twin to mumble something nonsensical. He shivered again and Grimlock and Sunstreaker simultaneously rolled closer to cuddle him.

                “Seemed like a lot of effort to kick you out,” Sunstreaker replied nonchalantly. “Besides, Sides might want a repeat later.”

                Grimlock blinked at him, surprised.

                It could be true; Sideswipe seemed the voracious type. Or maybe Grimlock’s assumption that Sunstreaker merely tolerated him was incorrect.  

                The hope that Sunstreaker was just as interested in furthering things as Grimlock made him a little giddy. He wanted to press further, but closed his optics instead. Sideswipe needed rest and Sunstreaker showed every indication of joining him.

                It took a few minutes for Grimlock to settle. The twins’ systems sounded far different than the other his brothers’ but he soon got used to the way their engines rumbled in sync with one another. Grimlock let himself drift into recharge like that, Sideswipe’s still hot frame nestled sweetly against him and his hand lightly resting on the small of Sunstreaker’s back.

                Prowl may have been angry about Sideswipe’s prank, but Grimlock could only be grateful for the series of events that had lead him here, to this promising tangle of bodies.

            

~ End

**Author's Note:**

> Cervical penetration/fucking is a misnomer. Unlike Sideswipe, we cannot open our cervix for dildos or penises to pass through so don't go trying that at home, kids. Cervical orgasms *are* a thing, however and are apparently Pretty Awesome, if you want to look that up.


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